The great appeal of outdoor activities during warm summer months means that there is a demand for related commodities. A preferred such activity is cooking foodstuff outside of the house, in the garden for example, over a barbecue grill. Typically, the heating fuel for these barbecue grills is charcoal; or, if trekking in isolated areas, locally available wood chips, or propane fuel (carried by the trekker) may be used.
Those seeking better value for their investment have developed the concept of transformer heating units, i.e. a single integral unit that can be easily transformed into various alternate modes. Typical of these modes are: foodstuff cooking units; radiating space heaters; frying, baking, steaming, roasting, and smoking units; for charcoal broiling; and including complementary means to serve with the cooking mode as a windbreak, as a dishpan or as a washpan.
Transformer heat-generating portable units have been known for a number of years. Such transformer units date back at least as early as the heating unit disclosed in U.S. Pat. No. 2,237,081 issued Apr. 1, 1941 to the Owens Smokeless Orchard Heater inc. corporation.
U.S. Pat. No. 2,907,316 issued in 1959 to Frank Windust further discloses a camp stove which can be transformed into a cooking unit or as a stove for use inside a tent.
U.S. Pat. No. 3,791,368 issued in February 1974 to William HUNT discloses a multi-purpose cooking assembly, which can be alternately used as a stove, as a griddle, as a toaster, as a pressure cooker, as a charcoal broiler, and for baking, steaming, roasting, or smoking foodstuff. This cooking assembly can be easily transported like a suitcase. It boasts a propane burner assembly for connection to a propane fuel reservoir, and/or alternate fuel source such as charcoal briquet in a suitable carrier, and/or prepackaged wood chips used when smoking the food. As suggested in FIG. 3 of the drawings in this latter patent, a variety of griddle, grill, carriers, pans, and other paraphernaliae are included as prepackaged detachable elements inside this cooking assembly, for use when necessary. For transport, these elements are generally nested into one another, as illustrated in FIG. 2, whereby support means 34, 38, 60 releasably interconnect these elements.
In U.S. Pat. No. 3,783,855 issued in January 1974 to Vann NEWINGER, there is disclosed a heat-radiating unit 12 pivotally mounted into a drawer-like casing. One face 62 of the unit 12 forms a grate made of heavy wire mesh, while the opposite face 58 of unit 12 forms a flat panel. When radiator 12 is pivoted to a first position where face 58 becomes horizontal and faces upwardly, foodstuff can be heated or fryed thereon; when radiator 12 is pivoted half a turn to a second position whereby face 62 becomes horizontal and faces upwardly, a barbecue surface is formed; and when radiator 12 is oriented vertically, as illustrated in FIG. 1, it becomes a space heater.
As we have seen, these transformer heating/cooking units are usually destined for outdoor use. Indeed, the combustion gases generated by the combustion of the fuel (charcoal or propane) are simply released to the air, without being channeled out through specific flue means. In the garden or in the woods, this has no drawback; but if one would like to use such a cooking/heating transformer unit inside a house or inside a flexible sheet tent, very real safety hazards would result, namely, severe intoxication (and possibly even death) from combustion gases (e.g. carbon monoxyde) smoke inhalation.